Circuit breaker



Dec. 17, 1935.

S. S. GRADY CIRCUIT BREAKER Filed April 30, 1951 n 2/ 29 l f4 3.5 30

lNvr-yo;` BY D f @may y Patented vDec. 17, 1935 UNITED STATES CIRCUITBREAKER Stephen S. Grady,

Magnolia, N. C., assigner to Fusoid Electric Co., Inc., a corporation ofNew York Application April 30, 1931, Serial No. 533,949

11 Claims.

This invention relates to circuit breakers and with regard to its morespecific features to such devices adapted for the protection of electriccircuits against excessive currents.

One of the objects of the invention is to provide a device of the abovenature practical and ecient and capable of meeting the requirements ofuse in a highly satisfactory manner. Another object is to provide adevice of the above nature simple in construction and at al1 timesdependable inaction. Another object is to provide a mechanical circuitbreaker adapted to take the place of cartridge fuses and co-act in anecient manner with the standard mountings provided ltherefor. Anotherobject is to provide such a device conveniently adjustable to thevarying conditions of practical use. Other objects will be in partobvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements,

and arrangements of parts as will be exemplified in the structure to behereinafter .described and the scope of the application of which will beindicated in the following claims.

In the accompanying drawing in which are l are shown one or more variouspossible embodlments of the several features of this invention.

Figure 1 is a side elevation of a circuit breaker, parts being cut awayto better disclose the structure.

Fig. 2 is an end view hand end of Figure 1.

Fig. 3 is a view similar to Fig. 2 .showing a slightly modified form,and

Fig. 4 is a sectional view of another modification.

Similar reference characters refer to similar parts throughout theseveral views of the drawing.

Referring now to the drawing, in detail, there is shown in Figure ilapair of metallic members shaped to provide parts and respectively ofrounded contour 'as shown in the end view of Figure 2. The part I0, asshown in this gure, terminates in lateral anged portions I2 and I3 and apair ofup-standing ears I4, the `part Il being shaped in a similarmanner and providing a similar pair of ears I5. These parts are formedof a suitable conductingV metal and are rigidly connected together by amember IB of insulating material which is secured to the flangedportions I2 and I3 of the part I0 and to 'corresponding flanged portionsof the part II. These rounded parts I0 and I I are so shaped and are sospaced by the member I6 as to t into and co-act with the standardcut-outs or fuse clips which are made to receive cartridge fuses ofstandard design and size. The spring clips of such a standardfusemounting are represented at II and i3 looking toward the leftwith themembers I0 -and I| respectively coating therewith in operative position.lIt may be here noted that the usual cartridge fuse mountings are madeaccording to different standard designs for cartridge fuses of differentcurrent capacities and that such mountings will be hereinafter lreferred to generally as standard fuse mountings.

It will be seen that the parts I0 and II are conveniently slipped intoplace in the clips I1 and I8, in place of the usual rounded end portionsof the ordinary cartridge fuse.

Opposite the member I6 is a member I9 of insulating material to whichis. secured, opposite the ears I4, a member 20 provided with a pair ofdepending ears 2|. The ears 2| are adapted to co-act with the ears I4 asshown inFgure 2 and make electrical connection therewith. Ad'- jacentthe other-end of the member I9 is secured a member 22 similar to themember 20 and provided with a pair of depending ears 23. The ears 23make electrical contact with the ears I5 of the part and are pivotedthereto as by a pin 24. `The member I9 therefore and the parts connectedtherewith are capable of swinging about the pin 24, the ears 2| therebymoving into or out of electrical contact with the ears I4.

. Carried bythe member I9 is a solenoid winding 25 connected byconductors 26 and 21 with the ears 2| and 23 respectively. Thereforewhen' the member I 9 with its connected parts is swung downwardly asviewed in Figure 1 so4 that the parts 2| and I4 are in contact, thecircuit is complete from the fuse clip I1 through the solenoid 25 to thefuse clip I8, and when the member I9 is swung to the position shown inFigure 1 the circuit in broken.

A flat spring 28 urges the member I9 and the parts carried thereby toswing outwardly to the position shown in Figure 1. Overhanging theleft-hand end of the member I9 is a latch member 29 adapted to co-,actwith a latch member 3|) to hold the parts in the position shown inFigure 2 against the action of the spring 28. The latch member 3D issuitably secured to lthe vmembers I6 and I0, for example, as at 3| and32. The latch member 29 terminates at its upper end in a rounded portion29a resting upon the upper surface of the member I9 and through anenlarged opening in which passes a screw 33 thread ed into the memberI9. Between the head ofthe screw 33 and in part 29Il is a compressionspring 34. The spring 34 thus tends to hold ythe'latch member 29 in theposition shown in the drawing. but upon movement of the lower part ofthe member 29 outwardly to disengage the latch member 3D the part 29arocks upon the surface of the member I9. Passing through the center ofthe solenoid 25 is a rod 35 preferably of brass or other suitablelnon-magnetic substance which .is vsupported at one end by a bracket 36secured to the member I9, and at the other end by the latch member 29through which it passes. The

l rod as is provided with a 'shouider 31 which limits acts in oppositionto the pull of the solenoid upon the part 39 and the rod 3 5. 'I'hemovement of th rod to the left therefore, under the urge of the solenoid25 or otherwise, through the shoulder 38, will release the latch member29 from engagement with the catch 30, thus permitting the spring 28 toswing the parts to the position shown in Figure 1, thus breaking thecircuit.

Considering now the action of the apparatusL when the parts are inposition of engagement as shown in Figure A2, current will flow betweenthe fuse clips |1 and I8 through the solenoid 25. 'I'he parts are soproportioned that when the current flowing exceeds a predetermined valuethe pull of `the solenoid 25 is sufficient to draw the part 39 inwardlyagainst the action of the springl 4|. 'I'he predetermined current atwhich this action takes place may be regulated or adjusted "i byadjustment of the compression in the spring these knife-like blades.

4|. Such movement of the part 39 through the rod 35 moves the latchmember 29 irom engagement with the catch 30 and the spring 281s free toswing the parts out of engagement to the position shown in Figure 1. Theears 2| and |4 therefore being out of engagement, the circuit is broken.Thus the circuit is automatically protected from the danger of excessiveflow of current and the value of the current at which thede'- vice willtrip may be adjusted. In order to insure further protection, if desired,a fuse 42 may be inserted in series with the solenoid, the fuse 42 beingadapted to blow at a 'slightly higher current vthan that at which thesolenoid ls set to move the rod 35.

The'circuit breaker may be operated manually at any time if so desired,substantially taking the place of an extra switch. The circuit may bebroken manually byy simply pushing the rod 35 tothe left by a thrust onits ,projecting righthand end, or the part 29a of the latch may berocked to release the catch. Inorder to reset the circuit breaker, `itis necessary to simply push the member |9 inwardly until the latch isagain in engagement. I'he circuit breaker may thus be operated manuallyfor either making or breaking the circuit in a highly convenient mannerwithout removing the device or in any way interfering with its mounting119011 the fuse clips |1 and |8. Furthermore, the *position of the partsat all times clearly indicates whether the circuit is complete orbreken.

'I'he larger sizes of standard make cartridge fuses are made withknife-blade contacts instead .f of the rounded contacts and the standardmountings vor fuse clips are accordingly made to receive *n ing of thistype is represented at 43 in Figure 3.

In order to co-act with this mounting the device above described inconnection with Figures 1 and f 2 is provided with knife-blade contacts45 instead ;of the rounded contact members I0 and As is shown in Figure3 the member forming the contact ears |4 is provided with a lateralportion-44 from the opposite side of which projects l standard fusemountf the knife-blade 45. It is tobe understood of course that, in thisinstance, the member forming the ears |5 at the otherfend of the device,is

insulating plug 46 about which is a threaded me- 15 tallic sleeve 41adapted to iit the threads of -a standard plug fuse mounting. At the endof the member 4 6 is a contact 48 serving as the other contact to makeconnection with the socket. The plug member 46 is,hollow and mounted 20therein is a solenoid 49 connected as will presently be described.

The ,plug Imember 46 is joined to an annular member 50 also ofinsulating material. Secured to this member 50, as at 5| and 52, is apair of 2 oppositely disposed metallic members 53 and 54 respectively.These members 53 and 54 are of a suitable conducting metal of resilientproperties, vand projecting upwardly to the interior of the annularmember 50, they tend to spring in- 30 .wardly toward each other. Betweenthese two contact springs 53 and 54 is gripped a member 55 of insulatingmaterial normally projecting from the interior of the annular member 5|)as shown. This memberv 55 is provided with an 35 yannular groove inwhich rests an annular conducting strip 56. The spring contacts 53 and54 are provided with inwardly directed projections 53a and 54arespectively which normally extend into the annular groove in the member40 55 making contact with the conducting strip 56 therein. The strip 56therefore normally makes electrical connection between the springcontacts 53 and 54 and the spring contacts serve to yieldingly hold themember 55 in the position shown l5 in the drawing.

Passing through the `member 55 and threaded therein is a, rod 51preferably formed of brass or other suitable non-magnetic substancewhich extends downwardly through the solenoid 49 and 50 is provided atits lower end with a member 58 of iron. Themember 58 therefore isadapted to be drawn inwardly by the solenoid 49 thus carrying thel rod51 and the member 55 upwardly against the action of the spring contacts53 and 55 54. The solenoid 49 is connected at one end to the contactmember 48 as by a conductor 59 and at the other end to the springcontact 53 as by a conductor 60. The other, spring contact 54 isconnected as by a conductor 6| with the contact 60 sleeve 41.

With the parts in normal operative position, as shown in the drawing,the circuit is thus completed from the contact member 48 through thesolenoid 49 to the contact sleeve 41. In the action o5 foi' the devicewhen the current through the solewith a screw head 62 positioned in' arecess in the top of the member 55 so that the rod 51 may beconveniently threaded in or out of the member 55 thus changing thenormal position of the iron member 58 with respect to the solenoid. Inthis manner the value of the current at which the solenoid will draw themember 5B upwardly against the action of the springs 53 and 5l may beconveniently adjusted. The lcircuit is thus automatically protectedagainst currents in excess of a predetermined value.

After the device has been tripped as above described, it isconveniently1 reset without removing the same from the fuse mounting by'simply' pushing the member 55 back into place; Furthermore, the devicemay be operated manually at any time to break the circuit, it beingnecessary to simply grasp the projecting member 55 and draw itoutwardly. The position of the part 55 indicates at all times `whetheror not the mechanism is in circuit closing position.

From the above it will be seen that there is herein provided apparatuswhich embodies the several features of this invention and attains theobjects thereof and that the apparatus is well adapted to meet therequirements of practical use. The mechanisms are simple inconstruction, at all times dependable in action and attain manypractical and useful advantages.

It will also appear that by means of the present invention, see theembodiment illustrated in Fig. l, when the device is used with a circuitof alternating current that when an over-load occurs so that the currentin the solenoid winding 25 attracts the core 39, the inductive reactancethereby established will automatically break the current even though thelatch member 29 did not clear the latch member 30 and the spring 28thereupon did not raise the bracket I9 to cause the contact between thecontacts 2| and Il to be broken.

In otherwords, the induction produced in the solenoid winding 25 notonly initiates the mechanical interruption of the circuit by actuationof the plunger 35 in turn to actuate the latch member 29y to permit thespring 2B to raise the bracket I9 but in addition thereto alsoelectrically interrupts the current due to the inductive reactance setup when the core 39 is moved into lthe winding 25.

It will also appear that, by means of this device, due to the fact thatthe current may be electrically interrupted by the inductive reactanceproduced when the solenoid winding 25 attracts the core 39, thesubsequent separation of the contact 2| from the contact i4 will occurwhen the current has already been broken so that arcing between thecontacts 2| and Il will be eliminated, if the current is so interruptedby the inductive reluctance before the plunger 35 has had an opportunityto free the latch member 30 from the latch member 29 by co-operationwith the spring 28.

As many possible embodiments may be made of the above invention and asmany changes might be made in the embodiment above set forth, it is tobe understood that all matter hereinabove set forth is to be interpretedas illustrative and not in a limiting sense.

I claim:

1. In apparatus of the class described, in combination, a pair ofmembers removably coacting with a pair of standard fuse clips and eachhaving exterior of said clips a lateral flange portion extending overthe outer edge of said clips, a

rigid base member of insulating material secured upon said Iiangeportions and positioned thereon exterior of the outer edges of saidclips, connecting said members together and holding the same in xedrelation to coact with said fuse clips, a mechanically operated switchconnecting said two members, and means adaptedto open said switch uponcurrent of predetermined value flowing therethrough, said switch beingadapted for manual closing with said members remaining in operativepositionin said fuse clips.

2. In apparatus of the ,class described, in combination, a memberyadapted to coact with one of a pair of standard fuse clips, formed ofsheet metal and having a part adapted to enter said fuse clips and apair of upstanding ears projecting outwardly therefrom, a second memberadapted to coact with the other of said'pair of fuse clips, a switchmember'electrically connected with said second member and having a partadapted to slide into position between and bear outwardly against saidpair of ears and to move into and out of engagement therewith to makeand break electrical connection between said two members, and meansadapted to move said part of said switch mechanism out of engagementwith said upstanding ears upon current of predetermined value flowingtherethrough.

3. In apparatus of the class described, in combination, a rigid basemember of insulating materialy a pair of members mounted thereon andadapted respectively to coact with a pair of standard fuse clips, a pairof upstanding ears elecIrica-lly connected with one of said members, asecond pair of upstanding ears electrically connested with the other ofsaid members, a switch member having one end pivoted upon one of saidpair of ears by a pivot pin passing through said ears and adapted toswing thereon and having a part adjacent the other end thereof adaptedto slide into and out of position between and in engagement with theother of said pairs of ears to make and break electrical connectionbetween said pair of members coacting with said fuse clips, and meansadapted to open said switgh upon current of predetermined value flowingtherethrough.

4. In apparatus of the class described, in combination, a rigid basemember of insulating material, a pair of contact members mounted uponsaid base member and adapted respectively to coact with a pair ofstandard fuse clips, an upstanding metal part adjacent one end of saidbase member electrically connected with one of said contact members, asecond`upstanding metal part adjacent the other end of said base memberand electrically connected with the other of said contact members, anarm of insulating material having adjacent each end thereof a projectingmetal part adapted respectively to engage said two upstanding metalparts on said base member and make electrical connection therewith,conducting means between said two projecting metal parts of saidinsulating arm, means pivotally vconnecting one of said projecting metalparts to said upstanding part on said base member with which it engages,and means adapted upon current of predetermined value flowing throughsaid conducting means to swing said arm about its pivot and move saidother projecting metal part thereon out of engagement with itscorresponding upstanding metal part on said base member.

5. In apparatus of the class described, in combination, a rigid basemember of insulating material, a pair of members thereon adaptedrespectively to coact with a pair of standard fuse clips, a switchinterposed between said two memopposition to said electro-magneticmeans, said adjusting means being accessible andoperative with said pairof members in operative position in said fuse clips.

6. In a circuit breaker for an electric circuit of alternating current,the combination with two terminals in the main line of the circuit, of abracket pivotally connected to one of said terminals, a xed latch membersecured to the other terminal, a movable latch member at the end of saidbracket, a solenoid winding mounted on said bracket and electricallyconnected in the main line of the circuit and to` said terminals whensaid, latch members are in locking engagement, a spring urging saidbracket into latch breaking position.' a non-magnetic plunger mounted onsaid bracket to actuate the latch member on said bracket; and a softiron core on said plunger normally disposed outside of said winding tobe attracted by the winding when an overload occurs to build inductivereactance to break the current electrically and to cause saidplunger toIactuate said movable latch member to permit said spring to actuate saidbracket to interrupt the current.

7. In a circuit breaker for an electric circuit ofalternating current,the combination with vtwo terminals in the main line of the circuit, ofa bracket pivotally connected to one of said terminals, a iixed latchmember secured to the other terminal, a movable latch member at the endof' said bracket, a solenoid winding mounted on said bracket andelectrically connecting said terminals in the main line of the circuitwhen said latch members are in locking engagement,-a spring urging saidbracket into latch breaking position, a non-magnetic plunger mounted onsaid bracket to actuate the latch member on said bracket; and a softiron core on said plunger normally disposed outside of said winding tobe attracted b y the winding when an overload occurs to build inductivereactance to interrupt the current electrically and to actuate saidplunger in turn to actuate the latch member on said bracket to permitsaid spring to actuate said bracket'out'of engagement with said otherterminal.

8. In a circuit breaker for an electric circuit A of alternatingcurrent, the combination with two terminals in the main line of thecircuit; of a frame 'pivotally connected to one of said terminals; aiixed latch member secured to the other terminal; a movable latch memberat the free end of said frame adapted .to cooperate withsaid fixed latchmember to anchor said frame in circuit making position; a spring urgingsaid frame into latch breaking position; and means for actuating saidvmovable breaking position when an overload occurs consisting in asolenoid winding electrically connected to one of said terminals, aplunger slidably mounted in said solenoid, and a soft iron core on saidplunger normally disposed outside of said of said terminals .ce ss; aspring finger connected to each latch member into latch on said frame;resilient means for anchoring said frame in position to bridge said twoterminals by said electrical conducto and means for moving said frameinto position to interrupt the current across said conductor when anoverload occurs including a solenoid winding electrically connected to`one of said terminals in the :nain line, a plunger mounted on saidframe and slidable in said solenoid winding, and a soft iron core onsaid plunger normally disposed outside of said winding to be attractedby the winding when an over- -load occurs `to build inductive reactanceto interrupt the current electrically and to cause said plunger toovercome the resilient connection between said resilient means and saidframe and thereby to release said frame into circuit breaking position.

l0. In a circuit breaker for an electric circuitr of alternatingcurrent, the combination with two terminals in the main line of thecircuit; of, a movable frame; a conductor mounted on said movable frame;a spring finger connected to each and positioned to engage osaidconductor and anchor said frame in circuit making position; and meansfor actuating said frame into iingerireleasing position and therebycircuit breaking position consisting in a solenoid Winding connected toone terminal in the main line, a plunger mounted onv said movable fr meand slidable in said Winding, and a soft iron core on said plungernormally disposed outside ofl said winding to be attracted by the.winding when an of alternating current, the combination with twoterminals in the main line of the circuit; of a movable frameconsistinglof a tapered plug composed of insulating material and havingan annular recess; an electricalconductor in said rea of said terminalsand positioned to enter said recess resiliently to anchor said plug andto contact said conductor in circuit making position; and means foractuating said .frame into finger releasing position and thereby circuitbreaking position conv -sisting in a solenoid winding connected to one`terminal in the main line, a plunger mounted on said movable frame andslidable in said winding, and a soit iron core on said plunger normallydisposed outside of said winding to `be attracted by the winding when anoverload occurs to build inductive reactance to break the currentelectrically and to actuate saidframe out of engagement of its conductorby said spring fingers and thereby into circuit breaking position. "I

STEPHEN s GRApY. 'i

